Is working in a telephone inquiry service that provides numbers for a fee, and sometimes charges are debited even if the number is unavailable due to system errors, permissible or forbidden? And is refraining from informing the official responsible for these errors considered a sin?

If the payment of the fee is merely for searching for a number in the database without guaranteeing its acquisition, then there is no harm, unless there is deception that misleads the caller into believing that the database contains all numbers. However, if the payment is for obtaining the number, then the fee should not be deducted unless the caller obtains the number, otherwise, it would be consuming people's wealth unjustly, and it is not permissible to continue working in it due to its involvement in cooperating in sin. It is obligatory to continue advising officials regarding Sharia violations.